As a conventional tire wears down its tread, the volume of the grooves between tread blocks is reduced, which can lead to poor hydroplaning performance. Conventional tires include a tread having a tread pattern that, when the tire is loaded, defines a footprint providing a frictional engagement with the road. The tread pattern is segmented into a plurality of raised blocks defined and separated by intersecting circumferential and lateral grooves. The grooves are necessary to provide flexibility and water removal, while the blocks determine the control, acceleration and braking characteristics of the tire. The circumferential grooves are positioned such that the raised blocks are arranged primarily in columns or ribs that extend circumferentially about the tire circumference.
The block dimensions, the number of ribs, and the inclination angle of the lateral grooves cooperate in determining the overall performance of the pneumatic tire. In particular, these factors determine the amount of tread that contacts the road, and hence the traction and control of the vehicle riding on the tires. The groove depth generally determines the ability of the intersecting circumferential and lateral grooves to channel water.
For a new tire, tread patterns are configured with compromises between various design parameters in order to optimize performance. As a tire wears, the parameter choices that optimized performance of the tire tread pattern in the unworn state may not be optimal at reduced groove depths. For example, a new tire construction may be designed with a tread pattern having raised blocks optimized for noise reduction and hydroplaning control. However, blocks that provide a balanced tire behavior in the new condition may not exhibit optimized noise reduction and hydroplaning control in a worn condition. Although the problem of noise created by contact between the road-contacting surfaces of the tread blocks and the road diminishes in a worn condition, current worn tires with conventional blocks are significantly more susceptible to hydroplaning than new tires.
For these and other reasons, it would be desirable to provide a tire tread with one or more tread blocks having one or more side walls with dimensions that address the deficiencies of conventional tire treads, in particular, worn hydroplaning performance.